JPH07104024A - Device for detecting grounding of wire harness - Google Patents

Abstract

PURPOSE:To detect the contact of an outer-fitting protecting material, which is provided for protecting electric wires of a wire harness, and a car body. CONSTITUTION:An alarm means formed of a LED 8 is connected between an outer-fitting protecting material made of conductive material and a (+) terminal of a battery 5, and a contact of the protecting layer with a car body is recognized when the LED 8 is lighted. In the case where a latch circuit is provided, when grounding is generated once, the LED 8 is continuously lighted, and in the case where a counter circuit is provided, when a predetermined frequency of grounding is generated, the LED 8 is lighted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting that an exterior protective material of a wire harness of an automobile is grounded on a vehicle body, which is detected before the exterior protective material is damaged and the wire harness is grounded on the vehicle body. This is to prevent a short circuit caused by contact between the vehicle body and the wire harness.

[0002]

2. Description of the Related Art A wire harness to be installed in an automobile is attached by an appropriate support so as not to come into direct contact with a vehicle body or an engine. In order to protect the electric wire, measures such as covering it with an exterior protective material such as a corrugated tube are taken.

[0003]

However, if vibration exceeding the design expectation occurs during the running of the automobile and the corrugated tube for protection comes into contact with the vehicle body or the like for a long period of time, the corrugated tube and the wire harness. There was a risk that the insulation coating of each wire would be damaged and the core wire of the wire would be grounded to the vehicle body, causing a serious accident.

The present invention has been made in order to solve the above-mentioned problems, and detects when the exterior protective material comes into contact with the vehicle body, and notifies the driver of the detection result by an alarm means, thereby wiring harnesses and the like. The purpose is to prevent the grounding accident of the electric wire of.

[0005]

In order to achieve the above object, as a first invention of the present invention, an outer protective material of a wire harness is made conductive, and the outer protective material and (+) of the battery are provided.
A grounding detection device for a wire harness, which is characterized in that a warning means is connected between the terminal and the terminal.

Further, as a second aspect of the present invention, there is provided a device for detecting that a conductive exterior protective material of a wire harness installed in an automobile comes into contact with a vehicle body, and is pulled up to a battery voltage by a resistance. And a level determination circuit for determining whether the potential (Vx) of the electrically conductive exterior protection material is lower than a predetermined voltage (V ₀ ), and the level determination circuit,
A latch circuit that latches a signal (Q) output when Vx <V ₀ is determined, and a signal output from the latch circuit
( Q ) switch means for turning on, and an LED provided so as to light when the switch means is turned on.
And a grounding detection device for a wire harness.

Further, as a third invention of the present invention, an output signal (Q) output from the level determination circuit and the latch circuit is provided.
A counter circuit that counts the number of outputs of the output signal is provided in the preceding stage of the latch circuit.
(EN) A ground detection device for a wire harness, which supplies a predetermined signal ( Q ') to a latch circuit by counting the output of (Q) a predetermined number of times.

When the above-mentioned conductive exterior protective material attached at a plurality of points is attached to one wire harness, a conductive joint for electrically connecting the plurality of exterior protective materials is provided, and the joint is provided. It is divided into two in the axial direction so that it can be attached to and detached from a plurality of conductive exterior protective materials.

The conductive exterior protective material and the joint are made of a corrugated tube for covering the wire harness and are made of conductive plastic. Alternatively, the conductive exterior protective material and the joint, the inner layer made of a conductive material,
An outer layer made of an insulating material is laminated. The conductive exterior protective material may be formed of a conductive tape, and the conductive tape may be wound around the outer peripheral surface of the wire harness.

As the above-mentioned conductive plastic, resin containing conductive carbon black, metal fibers, and metal-plated powder is preferably used.

[0011]

According to the first aspect of the present invention, when the electrically conductive exterior protective material comes into contact with the vehicle body having the same potential as the (-) terminal of the battery due to vibration or the like during traveling, the LED is lit through the exterior protective material. It will be connected between both terminals of the battery, which allows the LED to light up and alert the driver.

According to the second aspect of the present invention, in a normal state, the potential (Vx) of the conductive exterior protective material is the battery voltage.
Although it is pulled up to (V), if the conductive exterior protective material is grounded to the vehicle body, the potential (Vx) will drop and Vx <V ₀
Then, a signal (Q) is output from the level determination circuit, this signal (Q) is latched by the latch circuit, and the latch signal ( Q ) is supplied to the switch means to turn on the switch means. Causes the LED to light up.

According to the third aspect of the present invention, the signal (Q) is output from the level determination circuit each time the conductive exterior protective material is grounded, and the output frequency is counted by the unter circuit. When a predetermined number of times is reached, a predetermined signal ( Q ') is supplied from the counter circuit to the latch circuit, and the LED is turned on by the switch means that is turned on by the output signal ( Q ') of the latch circuit that latches this signal. .

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an electric circuit diagram showing an embodiment of the device of the first invention. Reference numeral 1 is a wire harness, and 2 is a conductive exterior protective material composed of a corrugated tube that covers the wire harness 1 for protection. The material of the conductive corrugated tube 2 is polyamide resin (for example, 66
Nylon) with conductive power 20PHR (weight ratio when the resin is 100), volume specific resistance 1.4 × 10 ² Ω · c
In addition to carbon black and carbon black, conductive plastics mixed with metal fibers, metal-plated powder, etc. can be used. Reference numeral 3 denotes a detection electric wire provided to detect the grounding of the conductive corrugated tube 2 to the vehicle body. One end (indicated by 3a ') of the core wire 3a is located on the corrugated tube 2 and the tape 4 The core wire 3a and the corrugated tube 2 are electrically connected by winding.

Reference numeral 5 is an automobile battery, of which (-)
The terminal 5a is connected (grounded) to the vehicle body G, and the (+) terminal 5b
Is connected to one end (anode) of the LED 8 through an ignition switch 6 and a current limiting resistor 7. L
The other end (cathode) of the ED (8) is connected to the other end (indicated by 3a ″) of the core wire 3a of the electric wire 3 for detection.
The alarm means consisting of is provided on the panel on which the instruments are arranged so that the lighting state can be easily seen by the driver.

In the above structure, if the conductive corrugated tube 2 comes into contact with the vehicle body G due to vibration during traveling, the cathode of the LED 8 will be grounded to the vehicle body G.
ED8 lights up.

FIG. 2 shows one embodiment of the second invention, and the same parts as those in FIG. 1 are designated by the same reference numerals. The other end 3a ″ of the core wire 3a of the detection electric wire 3 is connected to the ignition switch 1 via a current limiting resistor 11 at the time of grounding.
1 is connected to the secondary (load) side, and the battery voltage V is always applied to the core wire 3a and hence the corrugated tube 2. Reference numeral 12 is a level determination circuit for determining the potential Vx of the corrugated tube 2 and outputs a "high" output signal Q when Vx <V ₀ . Reference numeral 13 denotes a latch circuit, which latches the output signal Q and outputs an output signal (indicated by Q ) if the output signal Q is input even at an instant. The signal is supplied to the base of the switching transistor 14,
The emitter of the transistor 14 is grounded to the vehicle body G, and the collector thereof is connected to the cathode of the LED 8.

In the above circuit configuration, the potential Vx of the conductive corrugated tube 2 is V (> V ₀ ) under normal conditions. The potential Vx decreases according to the ground resistance, but when Vx <V ₀ now, the level determination circuit 12 outputs the above-mentioned output signal Q, and the latched circuit 13 latches the output signal Q. When Q is output, the transistor 14 is switched on and the LED 8 lights up. In this circuit configuration, the LED 8 is continuously turned on by the latch function of the latch circuit 13 even if the corrugated tube 2 is instantly grounded.

FIG. 3 shows an embodiment of the third invention, and differs from FIG. 2 in that a counter circuit 21 is inserted between the level judgment circuit 12 and the latch circuit 13.

In the above circuit configuration, the corrugated tube 2
The level determination circuit 12 outputs the above-mentioned output signal Q each time grounding occurs, and the counter circuit 21 counts each output as the number of times of grounding. When the number of grounding reaches a prescribed number, the counter 21 outputs " The output signal Q ′ of “high” is output. This signal Q ′ is latched by the latch circuit 13, and the output signal Q ′ latched by this latch circuit 13 is supplied to the transistor 13 so that the LED
8 is continuously illuminated.

2 and 3, the LED 8 is continuously lit by the latch circuit 13, but the lit state is reset by turning off the ignition switch 6.

In each of the above-mentioned embodiments, the corrugated tube 2 is used as the conductive protective layer, but FIG. 4 shows a modification thereof, in which one end 3a 'of the core wire of the detection electric wire 3 is connected to the wire harness 1. Then, the conductive tape 31 is wrapped around the wire harness 1 so as to wrap around this portion.

Further, in the above configuration including FIG. 4, if the corrugated tube 2 or the conductive tape 31 comes into contact with the vehicle body G, the circuit for detecting the ground immediately functions, but it is separately provided due to the contact with the vehicle body. The circuit for ground detection may be activated when the protective coating is damaged. The cross section of the wire harness part in that case is shown in FIG. Here, an insulating material 41 for protection is attached to the outer periphery of the conductive corrugated tube 2 that covers the wire harness 1.
The insulating material 41 may be extruded at the same time when the conductive corrugated 2 is extruded, or, like the tape shown in FIG. It may be wrapped around the outer circumference. The conductive corrugated tube 2 covered with the insulating material 41 is connected to the detection electric wire 3 as shown in FIGS.
It is connected to the ground detection circuit shown in (preferably FIG. 2).

The above-mentioned protective corrugated tube needs to be provided at each required position, and in that case, a ground detection circuit must be provided for each corrugated tube, which is inconvenient. Therefore, the present invention also provides a joint in which a plurality of corrugated tubes can be protected by a single ground detection circuit.

FIG. 6 shows the structure of a linear joint suitable for connecting two corrugated tubes. This straight joint 51
Can be divided into two parts in the axial direction so that the corrugated tube already inserted in the wire harness can be detachably covered. In the present embodiment, one cut end of each divided piece in the axial direction is formed. As shown in FIG. 6, they can be opened and closed with each other as a fulcrum. This straight joint 51 is
As shown in the sectional view of FIG. 7, a conductive plastic 71 and an insulating plastic 72 are double-formed with the conductive plastic 71 inside.

FIG. 8 shows an example of its use, which is shown in FIG. 6 by connecting both electrically conductive corrugated tubes 53 and 54, which are provided separately to one wire harness 52. By positioning the joint 51 in the open state and then closing the joint 51 in the open state, the corrugated tubes 53 and 54 are electrically connected via the conductive joint 51. Therefore, for example, if one corrugated tube 53 is connected to the above ground detection circuit,
Not only the ground accident in the corrugated tube 53 but also the ground accident in the corrugated tube 54 and the joint 51 can be detected.

Further, the wire harness is branched into a T shape,
A T-joint suitable for interconnecting the three corrugated tubes provided to cover those wire harnesses is shown in FIG. 9, and a sectional view taken along the arrow in the figure is shown in FIG. This T-shaped joint may be double-formed like the linear joint 51 of FIG. 7, but here, the polyamide resin is used.
(For example, 6.6 nylon) was mixed with conductive carbon black 20PHR in order to have conductivity, and a single material having a volume resistivity of 1.4 × 10 ² Ω · cm was formed. Although it may be of a half-split type as in FIG. 7, it is of a non-divided type here, so that the T-shaped joint 91 is inserted so that the corrugated tube inserted in the T-shaped joint 91 does not come off.
A groove 92 is formed at the end of the.

[0028]

As described above, according to the first aspect of the present invention, the LED is turned on when the conductive exterior protective material is grounded to the vehicle body.
Lights up to give an alarm, so that the driver can easily know that the exterior protective material has come into contact with the vehicle body. At this stage, since the outer protective material is still in contact with the vehicle body and the core wire of the wire harness is not in contact with the vehicle body, the alarm can prevent the wire harness and the vehicle body from being grounded.

According to the second aspect of the present invention, if the exterior protective material is grounded even once, the LED is continuously turned on, so that it is possible to know whether or not the exterior protective material is grounded. According to the third aspect of the invention, the LED is turned on when the grounding of the exterior protective material occurs for a predetermined number of times, so that the exterior protective material is in repeated contact with the vehicle body, which may damage the exterior protective material. You can know whether or not.

In addition, when a plurality of exterior protective materials are attached to one wire harness, the conductive joint provided by the present invention is used, and a plurality of wires inserted into one wire harness are inserted. A grounding accident can be detected by the single grounding detection circuit for the exterior protective material of.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram showing an embodiment of the device of the first invention.

FIG. 2 is a control block diagram showing an embodiment of the device of the second invention.

FIG. 3 is a control block diagram showing an embodiment of the device of the third invention.

FIG. 4 is a side sectional view showing a modified example of the wire harness portion shown in FIGS. 1 to 3.

FIG. 5 is a side sectional view showing a modification of the wire harness portion shown in FIGS. 1 to 3.

FIG. 6 is an exploded view showing a straight joint used to interconnect corrugated tubes used in the device of the present invention.

7 is a cross-sectional view of the linear joint of FIG. 6 taken along a direction orthogonal to the axial direction.

FIG. 8 is a diagram showing an example of use of the linear joint of FIG.

FIG. 9 is a perspective view of a T-joint used to connect corrugated tubes to each other used in the apparatus of the present invention in a T-shape.

10 is a sectional view in the axial direction of the T-joint of FIG.

[Explanation of symbols]

 1 Wire Harness 2 Conductive Corrugated Tube 3 Detection Wire 3a Core Wire 4 Tape 5 Battery 6 Ignition Switch 7 Resistance 8 LED 11 Resistance 12 Level Judgment Circuit 13 Latch Circuit 14 Transistor 21 Counter Circuit 31 Conductive Tape 41 Insulating Layer 51 Linear Joint 91 T-joint G body

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsushi Matsuoka 1-14 Nishisuehiro-cho, Yokkaichi-shi, Mie Sumitomo Wiring Systems, Ltd.

Claims (7)

[Claims] 1. A wire harness exterior protective material is made conductive, and between the exterior protective material and the (+) terminal of the battery,
A grounding detection device for a wire harness, characterized in that a warning means is connected. 2. A device for detecting a contact of a conductive exterior protective material of a wire harness arranged in an automobile with a vehicle body, the device being pulled up to a battery voltage by a resistor (11),
The electric potential (Vx) of the above-mentioned exterior protective material made conductive is a predetermined voltage.
Level determination circuit (12) for determining whether or not the voltage is below (V ₀ ).
And a latch circuit for latching the signal (Q) output when the level determination circuit (12) determines that Vx <V ₀
(13), switch means (14) that is turned on by the signal ( Q ) output from the latch circuit (13), and L provided so as to light when the switch means (14) is turned on.
An apparatus for detecting grounding of a wire harness, comprising: an alarm means including an ED (8). 3. A level determination circuit (12) and a latch circuit (1
4) is provided with a counter circuit (21) for counting the number of output times of the output signal (Q) output from the latch circuit (13), and the counter circuit (21) outputs the output signal (Q). The grounding detection device for the wire harness according to claim 2, wherein a predetermined signal ( Q ') is supplied to the latch circuit (13) by counting a predetermined number of times. 4. A conductive joint (51) for electrically interconnecting the conductive exterior protective material, wherein the conductive exterior protective material is attached at a plurality of positions with respect to one wire harness.
The grounding detection device for a wire harness according to any one of the preceding claims, characterized in that the joint is divided into two in the axial direction so that the joint can be attached to and detached from a plurality of conductive exterior protective materials. 5. The conductive exterior protective material and the joint are made of a corrugated tube covering a wire harness,
The grounding detection device for a wire harness according to claim 1, wherein the grounding detection device is formed of a conductive plastic. 6. The wire according to claim 1, wherein the conductive exterior protective material and the joint are configured by laminating an outer layer made of an insulating material on an inner layer made of a conductive material. Grounding detection device for harness. 7. The conductive outer protective material is made of a conductive tape, and the conductive tape is wound around the outer peripheral surface of the wire harness.
The grounding detection device for the wire harness according to item.